Court of Appeals: Sweat Serve

Before every first serve my opponent wipes the sweat from his brow with the ball. Won’t the ball, weighted with the sweat, react oddly when struck, like a spitball in baseball? Apart from the fact that it grosses me out, is the sweat serve legal?—Benjamin Farmer, Houston, TX

Not at all. USTA Comment 3.2 states that a player “may not take any action that materially changes the condition of the ball; therefore, a player may not use a ball to wipe off perspiration.” Tell your opponent to invest in a hat, headband, bandana or all of the above.

Except where noted, answers are based on the ITF Rules of Tennis and USTA's The Code.